The objective of this study was to investigate rheological properties of xanthan gum/starch mixtures. Gels of starches investigated showed pseudo-plastic properties and had a flow limit. A pap starch made of modified potato starch MSZ (acetylated distarch adipate) showed the highest viscosity. While cooling this pap, its viscosity continuously grew and was 127 mPa×s at a temperature of 25°C. Also, the MSZ starch gels had the highest flow limit (5.36 Pa). As for maize starches, the modified MKW starch (acetylated distarch adipate produced from waxy maize) proved to be of the lowest deformability. Its flow limit was 3.53 Pa. Among all starches studied, pap of the native potato starch NSZ proved to be the most resistant to shear forces. The addition of xanthan gum increased the apparent viscosity of MKW pap starch. A sample containing 0.1% of xanthan gum added had the highest viscosity (809 mPa·s) at 25ºC. The increase in the salt concentration (0.5M concentration of NaCl) evidently increased the viscosity of MKW-GK mixtures, which was 950 mPa·s at 25ºC. Low-fat mayonnaises (50% of fat) plus polysaccharides added had properties similar to properties of a mayonnaise containing 80% to 85% of fat. The best texture had mayonnaises with xanthan gum/starch mixture added at a rate of 1:4.
texture, flow limit, gelatinization temperature, apparent viscosity